Woven single layer or double-layer endless lifting slings are used in large quantities for lifting loads, according to European Standards EN 1492-1 (Safety: Requirements for flat-woven lifting slings of synthetic fibers) and EN 1492-2 (Safety: Requirements for round slings of synthetic fibers). FIG. 1 shows a view of a known, single-layer endless lifting sling according to EN 1492-1. These textile bands are sewn together so that they overlap, thus acquiring the suitable delivery form for the user.
According to U.S. Pat. No. 5,498,047, a textile, abrasion resistant lifting sling is known, in which the superposed woven zones are sewn together.
The very work-intensive sewing processes are disadvantageous there, and the original strength of the sling is thereby reduced. For this reason, the strength of the sling used has to be chosen considerably higher than would be prescribed for the application provided. Investigations have shown that a replacement of the sewing process by welding or adhesion is seriously faulty for safety reasons. Bonding has been accepted in only a few uses in which strength or breaking load plays a subordinate part. Weld seams on textile bands have the disadvantage that a weakening of the material occurs directly adjacent to the weld seam to a greater or lesser extent.
It is furthermore known that several woven layers can be woven directly one above another with so-called needle looms for textile bands. The connection between the fabric layers, however, has up to now been found to be unsuitable for use in lifting slings. It has now surprisingly been found that a suitable overlapping of two woven fabric layers woven one above the other and a special woven construction according to the invention can lead to a suitable and reliable breaking load for endless lifting slings.